The present invention relates to an optical axis adjustment device and an automatic optical axis adjustment system, and more particularly to a technique for adjusting the angle and position of a light beam using a simple optical system. The present invention relates further to an exposure apparatus having an optical axis adjustment function, and more particularly to an exposure apparatus that requires a highly accurate optical axis adjustment to be used when, for example, providing a hologram image on a photosensitive material layer.
A light beam is widely used in various industrial fields such as exposure process for micro-patterns, material working process, and information communication. In optical systems utilizing a light beam, it is important to adjust the optical axis, and particularly, in processes for accurate processing utilizing laser beams, etc., it is necessary to perform an optical axis adjustment with accuracy. Common optical axis adjustment devices for a light beam are constituted by incorporating optical elements such as reflectors and prisms.
As a method of forming micro-patterns using a light beam, the method for illuminating a predetermined exposure plane and of partially exposing a photosensitive material layer disposed on the exposure plane is widely used in manufacturing processes for semiconductor devices, forming processes for hologram images, etc. Exposure apparatuses used in such exposing operations generally have a structure of guiding an exposure beam generated in a beam source to an exposure plane, expanding the beam diameter as appropriate, and illuminating the exposure plane. In order to guide an exposure beam to an appropriate position, it is important, in the optical system for guiding the exposure beam, to adjust the position of the optical axis with accuracy. The optical axis adjustment for a light beam may be performed by an operator in a visual and manual manner or may be performed by an automatic control based on an output signal from a position sensor for a light beam, using a device incorporating optical elements such as reflectors and prisms as mentioned above.
However, conventional common optical axis adjustment devices, which employ a complex optical system incorporating reflectors and prisms, suffer from a problem of having a complex overall structure. There is also a problem in that since the number of reflections within such devices is increased, there occurs a loss in the light intensity of a light beam passing therethrough.